Projectile.



No. 863,248. 'PATENTED AUG. 1s, 1907.

C. DE ZFRA.

PROJEUTILE. APPLIOATION FILED DEo.1o.19o a.

CARLOS DE ZAFRA, OF NEW YORK, N. Y.

PROJECTILE.

To all whom it 'may concern:

Be it known that I, CARLOS DE ZAFRA, a citizen of the United States, residing at N ew York city, county of New York, and State of New York, have invented certain new and useful Improvements in Projectiles,

of which the .following is a specification.

My invention relates to an improved form of explosive shell or other projectile, Vand more particularly to those projectiles which are reinforced by longitudinalribs.

It further relates to a method whereby such a projectile may be made.

The object of my inventionl is to provide a shell having a maximum strength or perforating power, 4together withav maximum capacity for an explosive charge, and the invention consists in forming the projectile with the bers or grain ofthe metal running in 'a spiraldirection from the base of the shell tothe top thereof, and in reinforcing the interior of the shell with ribs'which shall run in the same'direction, starting at the base of the projectile and ending atl the'top end of the inner chamber.

In the drawings, Figure 1 is a side view oi a projectile, the grain or fiber of which is indicated by dotted lines. Fig. 2 is a longitudinal section showing the interior `ribs. i Fig. 3 is a transverse section on the line 3 3, Fig. 2.

' While the tendency to rupture is very much lessened by the use of straight longitudinal ribs lon the interior of shells and projectiles of 'various kinds, yet such a straight longitudinal rib is itself liable to a sheering and disruptive stress along transverse lines when the projectile strikes, due to the rotative inertia of the projectile in its flight.

The aim of my invention is to provide ribs which will be coincident witluthe rotative travel of the shell Y so that when the point of the projectile enters an armor plate, the stress of this sudden stoppage of rotation will be taken up along the fiber or grain of the shell and by the spiral ribs therein. Thus the sheering tendency of the metal in the walls of the shell is greatly reduced and greater strength is given to resist the tendency of the rear end of the shell to twist off, due to the rota` tory course when the vhead of the shell is embedded in an armor plate. l Like letters in the figures designate like parts.

A represents the shell, and B'the fuse, B being the rotating band which is secured on.the shell near the base in the usual way. The hollow portion of the shell consists oi a chamber C extending from the base to the forward end of thecshell. The walls of this chamber are provided with the ribs D extending from the base to the point of the chamber in a spiral direction. In the drawings, I have shown the pitch of this spiral as Specification of Letters Patent.

Application filed December 10, 1908. Serial No. 347.055.

Patented Aug.y .1?9075. l

" *of a one quarter turn in the length of the chamber, but it is to be understood that I may use a greater or less pitch without departing in any way from my invention.'

I.have shown a pitch of one quarter turn particularly for purposes of illustration, as if a greater pitch had been used the sect-ion'Fig. 2 would not have shown any one rib entirely.

As will be seen by Fig. 1, the grain or fiber of the metal is also twisted spirally in accordance with the pitch of the ribs D, in this case a quarterturn from the rear end of the projectile to its point.

.In order to manufacture a projectile of this characte I hav devised uio following method whioh I doom preferable, though I do not wish to limit myself thereto. This consists first in casting an ingot from which the solid forging is to be produced. Previous to, during or torsion apparatus, one end of the ingot being held fixed while the other end is being rotated by anysuitable rotative gripping mechanism through an arc of the number of degrees desired. This will result in what I term a twist forging in which the grain or fiber will lie in any predetermined or desired spiral directiolt'o'r pitch. Thepiral ribs which are to lie in the direction preferably parallel to the grain orfiber of the metal may now be formed by the boring process similarto' thatemployed in the riding of modern artillery.

'My projectile might also be formed by forming the shell with the ribs longitudinally therealongv in a direct line from front to rear and with the fiber-of the metal also running in a direct line parallel with the ribs. The projectile might then be :cheated for forging and while being forged the rear could beheld inany suitable gripping device and the'orward end be rotated, as before explained. Thus the fiber of the shell and the interior ribs will both be given the spiral twist desired.

It will be seen that with either of these processes the fiber of the shell and the spiral ribs lie parallel to each other and are most perfectly formed ,to resist the shock of impact, the reaction of which will be along the line coincident with the resultant ofthe angular or rotative and the trajectoral velocities, which line will lie parallel with the spiral ribs, the pitch of `such ber and ribs having been predetermined by suitable calculation. The above described methodspwhile not claimed herein areto form the subject matter of a separate application.

Having described my invention what I claim is: f 1. A projectile provided with a chamber extending along its length, the walls ot said chamber. being provided with longitudinal ribs extending in a spiral direction from the base of the chamber to the forward end thereof.

2. A projectile provided with a chamber extending along its length, the forward` end of said chamber being pointed, the walls of said chamber being provided with longitudinal ribs extending in a spiral drectionfrom the base of the chamber to the point thereof. l

3. A projectile having the bers of its material twisted in a spiral direction from the base of sn'd projectile.to. the end thereof.

4. A projectile haying the bers of its material twisted in a spiral direction from the base of said projectile tothe and thereof, said projectile having-a ycentral chamber, the 'inlis of which are provided with longitudinal ribs extendthis sixth day of December 1906;

ing iii sprui direction from the base of the chamber toi 1() the point thereof: 4 v

rIn testimony whereof, I have signed my n ame to this specication in the presence of two subscribing Witnesses,

y CARLOS DE ZAFRA.

Witnesses:

Emmo Bamm, EMMA Ronnmcx, 

